Method for producing image display apparatus

ABSTRACT

Exemplary embodiments enable a high-luminance and high-contrast image to be displayed so that there are no defects resulting from deforming an image display part, the curable resin composition has a uniform thickness, and air bubbles are prevented in the curable resin composition. A method for producing an image display apparatus including coating a curable resin composition onto a base, arranging the base and the protective part to face each other, and forming a cured resin layer between the base and the protective part, wherein a resin composition has a curing shrinkage ratio of 5% or less, a cured product storage modulus of 1×107 Pa or less at 25° C., and a light transmittance in a visible region of 90% or more, and the curable resin composition coated onto the base or the protective part has a pattern with a prescribed shape.

TECHNICAL FIELD

The present invention relates to a method for producing an image displayapparatus, such as a liquid crystal display apparatus (LCD), used in acellular phone, for example. In particular, the present inventionrelates to a method for producing an image display apparatus providedwith a transparent protective part on an image display part.

BACKGROUND ART

Conventionally, as this type of image display apparatus, a liquidcrystal display apparatus 101 illustrated in FIG. 9, for example, isknown. This liquid crystal display apparatus 101 has a transparentprotective part 103 made of, for example, glass or plastic on a liquidcrystal display panel 102.

To protect the surface of the liquid crystal display panel 102 and apolarizing plate (not illustrated), a spacer 104 is arranged between theliquid crystal display panel 102 and the protective part 103 to form agap 105 between the liquid crystal display panel 102 and the protectivepart 103.

However, the gap 105 between the liquid crystal display panel 102 andthe protective part 103 scatters light, resulting in decreased contrastand luminance. The presence of the gap 105 also makes it difficult toproduce thinner display panels.

To address these problems, it has been proposed to fill the gap betweenthe liquid crystal display panel and the protective part with a resin(for example, Patent Document 1). However, the stress generated duringthe curing shrinkage of the cured resin causes an optical glass platesandwiching the liquid crystals in the display panel to deform,resulting in image defects such as disrupted orientation of the liquidcrystal material.

Furthermore, in the case of filling the gap between the liquid crystaldisplay panel and the protective part with a resin, the resin may becoated on either the liquid crystal display panel or the protective partand then the liquid crystal display panel and the protective part may belapped. However, when employing such a method, it is difficult touniformly form the thickness of the resin between the liquid crystaldisplay panel and the protective part. Moreover, there is also theproblem that air bubbles can become mixed in the filled resin.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2005-55641

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The present invention was conceived of considering such problems in theconventional art. It is an object of the present invention to provide atechnique concerning the production of a thin image display apparatushaving a resin arranged between an image display part and a protectivepart. According to this technique, display defects resulting fromdeformation of the image display part are not produced, an image can bedisplayed with high luminance and high contrast on the display part, thethickness of a curable resin composition filled between the imagedisplay part and the protective part is uniform, and air bubbles areprevented from becoming mixed in the curable resin composition.

Means for Solving the Problems

To achieve the above-described objects, the present invention provides amethod for producing an image display apparatus which includes the stepsof: coating a curable resin composition onto a base having an imagedisplay part or onto a light-transmitting protective part arranged onthe image display part; arranging the base and the protective part toface each other in close proximity; and forming a cured resin layerbetween the base and the protective part by curing the curable resincomposition, wherein

as the curable resin composition, a resin composition is used which hasa curing shrinkage ratio of 5% or less, a cured product storage modulusof 1×10⁷ Pa or less at 25° C., and a light transmittance of the curedresin layer in a visible region of 90% or more, and

the curable resin composition coated onto the base or the protectivepart has a pattern with a prescribed shape, the curable resincomposition is made to spread between the base and the protective partdue to the base and the protective part being arranged facing each otherin close proximity, and then the curable resin composition is cured.

In the present invention, the pattern of the curable resin compositionmay be formed from a center pattern positioned in a center portion of acoating face of the base or the protective part, and corner patternswhich are positioned closer to the corners of the coating face than thecenter portion and which are continuous with or separated from thecenter pattern.

In the present invention, the pattern of the curable resin compositionmay be formed from a plurality of patterns arranged at an interval.

In the present invention, the curable resin composition may be coatedonto the base or the protective part, and then the base and theprotective part are arranged facing each other in close proximity in astate where the coating face faces perpendicularly down.

In the present invention, the curable resin composition may be coated onboth the base and the protective part.

In the present invention, the image display part may be a liquid crystaldisplay panel.

In the present invention, the protective part may be formed from anacrylic resin.

In the present invention, the protective part may be formed from anoptical glass.

Effects of the Invention

The internal stress which builds up during curing of the resin can beapproximated by the product of the after-curing storage modulus and thecuring shrinkage ratio. Furthermore, according to the present invention,a curable resin composition having a curing shrinkage ratio of 5% orless and a cured product storage modulus of 1×10⁷ Pa or less at 25° C.is used as the curable resin composition which is arranged between theimage display part and the protective part. Thus, the effects of stressto the image display part and the protective part during curingshrinkage of the resin can be suppressed to a minimum. Therefore, hardlyany distortion is produced in the image display part and the protectivepart. Consequently, according to the present invention, an image can bedisplayed which is free from display defects and which has highluminance and high contrast.

Especially, when the image display part is a liquid crystal displaypanel, high-quality image display can be achieved by reliably preventingimage defects such as disrupted orientation of the liquid crystalmaterial.

Furthermore, according to the present invention, the image displayapparatus is stronger against shocks because a cured resin is arrangedbetween the image display part and the protective part.

Moreover, compared with the conventional example, in which a gap isprovided between the image display part and the protective part, athinner display apparatus can be provided.

In addition, according to the present invention, concerning thearrangement of the curable resin composition between the image displaypart and the protective part, the curable resin composition is coated ina specific pattern onto the base having the image display part or ontothe protective part, and the base and the protective part are arrangedfacing each other in close proximity. Consequently, the curable resincomposition can be made to rapidly and completely wetly spread betweenthe base and the protective part in a uniform thickness, and air bubblescan be reliably prevented from becoming mixed in the curable resincomposition.

Furthermore, in the present invention, if the curable resin compositionis coated onto the base or the protective part, and then the base andthe protective part are arranged facing each other in close proximity ina state where the coating face faces perpendicularly down, it is moredifficult for the surface shape of the curable resin composition to beinfluenced by the surface shape of the coating face of the base or theprotective part. Furthermore, the coated surface of the curable resincomposition pattern is smoother due the combined forces of gravity andresin surface tension. Therefore, the thickness of the curable resincomposition between the base and the protective part can be made moreuniform, and air bubbles can be reliably prevented from becoming mixedin this resin composition.

Especially, concerning coating the curable resin composition in aspecific pattern, if the curable resin composition is formed into acenter pattern positioned in a center portion of a coating face of thebase or the protective part, and corner patterns which are positionedcloser to the corners of the coating face than the center portion andwhich are continuous with or separated from the center pattern, when thecurable resin composition wetly spreads due to the arrangement of thebase and the protective part facing each other in close proximity, thecurable resin composition can be made to rapidly spread across allregions between the base and the protective part without the curableresin composition protruding from the edges of the base and theprotective part.

In this case, due to the corner patterns, the curable resin compositioncan be made to wetly spread along the edges of the base and theprotective part.

In the present invention, if the curable resin composition pattern isseparately formed both on the base and the protective part, the coatingof the curable resin composition can be carried out in separate stepsfor the base and the protective part. This allows the production stepsto be speeded up even further.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1(a) to 1(d) are cross-sectional process diagrams illustrating themain parts of an embodiment of the production method according to thepresent invention.

FIG. 2 is a plan diagram illustrating the main parts of the steps forproducing a display apparatus according to the same embodiment.

FIG. 3 is a diagram schematically illustrating an example of a resincomposition pattern according to the present invention.

FIG. 4 is a diagram schematically illustrating another example of aresin composition pattern according to the present invention.

FIG. 5 is a diagram schematically illustrating yet another example of aresin composition pattern according to the present invention.

FIG. 6 is a diagram schematically illustrating yet another example of aresin composition pattern according to the present invention.

FIGS. 7(a) and 7(b) are diagrams schematically illustrating yet anotherexample of a resin composition pattern according to the presentinvention.

FIG. 8 is a diagram schematically illustrating an example of a resincomposition pattern of a comparative example.

FIG. 9 is a cross-sectional diagram illustrating the main parts of animage display apparatus according to the conventional art.

DESCRIPTION OF THE REFERENCE NUMERALS

-   1 Image display apparatus-   2 Base-   3 Protective part-   3 a Coating face-   4 Light-transmitting member-   5 Shielding part-   5 a Bonding face of the shielding part-   6 Frame-   6 a Bonding face of the frame-   8 Liquid crystal display panel (image display part)-   11 Curable resin composition-   12 Resin composition filled portion between the shielding part and    the base-   13 Resin composition filled portion corresponding to the image    display region-   14 Cured resin layer-   20, 20B, 20C, 20D . . . Resin composition pattern-   21 Center pattern-   22 a, 22 b, 22 c, 22 d . . . Arm portion pattern-   23 a, 23 b, 23 c, 23 d . . . Arm portion pattern end-   24 a, 24 b, 24 c, 24 d . . . Circular resin composition pattern-   32, 33 UV-rays

BEST MODE FOR CARRYING OUT THE INVENTION

A preferred embodiment of the present invention will now be describedwith reference to the drawings. In the drawings, same-numbered referencenumerals represent the same or a similar structural element.

FIGS. 1(a) to 1(d) are cross-sectional process diagrams illustrating themain parts of an embodiment of the method for producing an image displayapparatus according to the present invention. FIG. 2 is a plan diagramillustrating the main parts of the steps for producing an image displayapparatus according to the same embodiment.

As illustrated in FIG. 1(d), in the present embodiment, a base 2, havingan image display part 8 which is connected to a not-illustrated drivecircuit and displays a given image, and a protective part 3 are bondedtogether by a cured resin layer 14.

Applications of an image display apparatus 1 are not especially limited.The image display apparatus 1 may be applied in various products, forexample, in an image display apparatus such as a cellular phone, aportable game device and the like. The present invention will bedescribed below using as an example the case of producing a liquidcrystal display apparatus.

The protective part 3 is formed from a light-transmitting member 4 whichis about the same size as the base 2 and is plate-like, a sheet-like, orfilm-like. As the light-transmitting member 4, it is preferred to use,for example, optical glass or plastic (an acrylic resin such aspolymethyl methacrylate and the like). An optical layer, such as ananti-reflection film, a shielding film, a viewing angle control film andthe like, may also be formed on the surface or a rear surface of theprotective part 3.

A black box-shaped shielding part 5, for example, is provided on aperipheral region of the face on the base 2 side of thelight-transmitting member 4 (hereinafter referred to as a “coating face3 a”). This shielding part 5 is formed in a layer form with a uniformthickness by a printing method, for example.

The flatness of the coating face 3 a of the protective part 3 is notespecially limited. However, from the standpoints of the ease with whichthe resin wetly spreads and preventing air bubbles from becoming mixedin, the coating face 3 a is preferably as flat as possible.

On the other hand, the base 2 has a box-shaped frame 6, for example. Aliquid crystal display panel (image display part) 8 is mounted on aregion on the inner side of this frame 6. Furthermore, a backlight 7 ismounted on a position on the apparatus back side of this liquid crystaldisplay panel 8.

In the present embodiment, a bonding face 6 a of the frame 6 of the base2 and a bonding face 5 a of the shielding part 5 of the protective part3 are parallel with each other.

In the present embodiment, concerning the bonding of the protective part3 with the base 2, first, as illustrated in FIG. 1(a), a given amount ofa photocurable resin composition, for example, is dropped onto thesurface on the side on which the shielding part 5 of the protective part3 is provided, to form various patterns of the curable resin composition11.

The dropping amount of the curable resin composition 11 is preferablyset so that the thickness of the cured resin layer 14 after bonding theprotective part 3 and the base 2 together is 50 to 200 μm.

Furthermore, in the embodiment illustrated in FIG. 1, the pattern of thecurable resin composition 11 is formed on the protective part 3.However, in the present invention, the pattern of the curable resincomposition 11 may be coated on the base 2, or the pattern may bedivided up and coated on the protective part 3 and the base 2.

From the standpoints of making the curable resin composition 11 spreadin a uniform thickness between the base 2 and the protective part 3, andpreventing air from becoming mixed in the curable resin composition 11,it is preferred to form the pattern of the curable resin composition 11by coating the curable resin composition 11 so that when the base 2 andthe protective part 3 are arranged facing each other in close proximity,the curable resin composition spreads across the whole of the opposingfaces of the base 2 and the protective part 3. More specifically, it ispreferred to form the pattern of the curable resin composition 11 from acenter pattern positioned in the center portion of the coating face ofthe base 2 or the protective part 3, and corner patterns which arepositioned closer to the corners of the coating face than this centerportion and which are continuous with or separated from the centerpattern. This pattern may be formed from a plurality of patternsarranged at a given interval between each other.

FIGS. 3 to 7 schematically illustrate specific examples of the resincomposition pattern when the curable resin composition 11 is coated onthe coating face 3 a of the rectangular protective part 3.

First, a resin composition pattern 20 illustrated in FIG. 3 is formedfrom the curable resin composition 11 in a continuous shape in which thelower sides of roughly the letter Y are linked together.

This resin composition pattern 20 is formed symmetrical with the longside and the short side directions (XY directions) of the protectivepart 3. The resin composition pattern 20 is arranged on the protectivepart 3 so that the center of gravity of the resin composition pattern 20matches the center of gravity (point G) of the protective part 3.

This resin composition pattern 20 is formed from a center pattern 21positioned in the center region of the coating face 3 a of theprotective part 3, and corner patterns which are positioned closer tothe corners of the coating face 3 a than the center pattern 21.

More specifically, the center pattern 21 is formed in a belt-likepattern extending linearly in the above-described X direction. Thecorner patterns are formed as arm portion patterns 22 a, 22 b, 22 c, and22 d which branch out and extend in four directions from either end ofthe center pattern 21.

These arm portion patterns 22 a to 22 d are linearly provided alongreference lines 4 a to 4 d which extend toward each of the corners ofthe protective part 3 from either end of the center pattern 21.Consequently, the ends 23 a to 23 d of the arm portion patterns 22 a to22 d are positioned close to each of the corners of the protective part3.

The thickness of each portion of the resin composition pattern 20 doesnot always have to be uniform. In the present invention, the preferredthickness distribution of the resin composition pattern 20 depends onthe shape of the resin composition pattern 20. However, from thestandpoint of reliably preventing air bubbles from becoming mixed in theresin when filling the resin between the base 2 and the protective part3, it is preferred to make the thickness of the resin compositionpattern 20 at the center region of the coating face 3 a of theprotective part 3 thicker than the thickness of the resin compositionpattern at the peripheral region.

The resin composition pattern 20B illustrated in FIG. 4 is formed from aplurality of patterns arranged at a given interval on the coating face 3a of the protective part 3.

Specifically, similar to the resin composition pattern 20 illustrated inFIG. 3, the resin composition pattern 20B illustrated in FIG. 4 also hasa shape formed by linking the letter Y together. However, the armportion patterns 22 a to 22 d extending toward each of the corners ofthe protective part 3 from the center portion are shorter than the armportion patterns 22 a to 22 d illustrated in FIG. 3.

Furthermore, circular resin composition patterns 24 a, 24 b, 24 c, and24 d are respectively provided between the ends 23 a to 23 d of the armportion patterns and each of the corners of the coating face 3 a of theprotective part 3. These circular resin composition patterns 24 a to 24d are arranged on the above-described respective reference lines 4 a to4 d of the respective corner regions of the coating face 3 a of theprotective part 3.

The examples illustrated in FIGS. 5 and 6 correspond to modifiedexamples of the resin composition pattern 20B illustrated in FIG. 4.

The resin composition pattern 20C illustrated in FIG. 5 has arectangular pattern, which is roughly a similar shape to the protectivepart 3, as the center pattern 21 positioned in the center region of thecoating face 3 a of the protective part 3, and circular resincomposition patterns 24 a to 24 d between the four corners of the centerpattern 21 and each of the corners of the coating face 3 a of theprotective part 3, which are separated from the center pattern 21, ascorner patterns.

The resin composition pattern 20D illustrated in FIG. 6 has a circularpattern as the center pattern 21 positioned in the center region of thecoating face 3 a of the protective part 3, and circular resincomposition patterns 24 a to 24 d between the center of that circularpattern and each of the corners of the coating face 3 a of theprotective part 3, which are separated from the circular pattern, ascorner patterns.

FIG. 7 illustrates examples of the pattern arranged on both theprotective part 3 and the base 2 when the resin composition pattern isformed from a plurality of patterns arranged at an interval.

More specifically, FIG. 7(a) has the circular center pattern 21 of theresin composition pattern 20D of FIG. 6 arranged in the center region ofthe protective part 3. FIG. 7(b) has the circular resin compositionpatterns 24 a to 24 d of the same resin composition pattern 20D arrangedin the corner regions of the base 2.

In this case, the circular resin composition patterns 24 a to 24 d canalso be arranged at the corner regions of the protective part 3 and thecenter pattern 21 at the center region of the base 2. However, from thestandpoint of preventing air bubbles from becoming mixed in, it ispreferred to arrange the center pattern 21 on the protective part 3 andthe circular resin composition patterns 24 a to 24 d on the base 2.

In any of the above-described examples, the curable resin composition 11can rapidly and completely wetly spread between the base 2 and theprotective part 3 in a uniform thickness, and air bubbles can beprevented from becoming mixed in the curable resin composition 11.

Especially, by forming the curable resin composition 11 as the centerpattern 21, when the curable resin composition 11 wetly spreads betweenthe base 2 and the protective part 3, it is more difficult for thecurable resin composition 11 to protrude from the edges of the base 2and the protective part 3. Furthermore, by forming the curable resincomposition 11 as the corner patterns (arm portion patterns 22 a to 22d, circular resin composition patterns 24 a to 24 d), the curable resincomposition 11 can be wetly spread along the edges of the base 2 and theprotective part 3.

Moreover, for example, as illustrated in FIGS. 4 to 7, when the resincomposition pattern is formed from a plurality of patterns arranged at agiven interval, the curable resin composition 11 can be arranged andfilled in an optimum state at the respective regions of the base 2 andprotective part 3 based on the state of a device, such as the liquidcrystal display panel 8, the overall shape and the like.

In addition, for example, as illustrated in FIGS. 7(a) and 7(b), byarranging the center pattern 21 of the resin composition pattern 20D onthe protective part 3, and the circular resin composition patterns 24 ato 24 d thereof, which are corner patterns, on the base 2, thesepatterns can be formed by separate steps from each other. This allowsthe production steps to be speeded up even further.

In the present invention, the shape, thickness and the like of the resincomposition pattern are not limited to the examples described above.These may be appropriately changed according to the shape and the likeof the panel of the image display apparatus 1.

Furthermore, the resin composition pattern may also be formed by aprinting method.

As the curable resin composition 11 for forming the resin compositionpattern, a curable resin composition is used which is prepared such thatthe cured resin of that resin composition has a storage modulus (25° C.)of 1×10⁷ Pa or less, and preferably of 1×10³ Pa to 1×10⁶ Pa, arefractive index of preferably of 1.45 or more to 1.55 or less, and morepreferably of 1.51 or more to 1.52 or less, and a transmittance of 90%or higher in the visible region when formed into a 100 μm-thick layer.

Typically, even when the main resin component forming the curable resincomposition is the same, if an additionally-added resin component ormonomer component is different, the cured resin formed by curing suchcurable resin composition may have a storage modulus (25° C.) thatexceeds 1×10⁷ Pa. A resin composition that forms such a cured resin isnot used as the curable resin composition 11.

The curable resin composition 11 is prepared so as to have a curingshrinkage ratio of 5.0% or less, preferably 4.5% or less, morepreferably 4.0% or less, and still more preferably 0 to 2%.Consequently, the internal stress that builds up in the cured resinduring curing of the curable resin composition 11 can be reduced, andthe distortion at the interface between the cured resin layer 14 and theliquid crystal display panel 8 or the protective part 3 can beprevented. Thus, by arranging the curable resin composition 11 betweenthe liquid crystal display panel 8 and the protective part 3 and thencuring the curable resin composition 11, the amount of light scatteredat the interface between the cured resin layer 14 and the liquid crystaldisplay panel 8 or the protective part 3 can be reduced. As a result,the luminance and the visibility of the display image can be improved.

The magnitude of the internal stress that builds up in the cured resinduring curing of the resin composition can be evaluated by dropping theresin composition onto a flat plate, curing the dropped resincomposition, and measuring the average surface roughness of theresultant cured resin. In practice, the distortion generated at theinterface between the liquid crystal display panel 8 or the protectivepart 3 and the cured resin arranged in between can be ignored if, forexample, a cured resin obtained by dropping 2 mg of the resincomposition onto a glass plate or an acrylic plate and curing by UVirradiation to a 90% or higher cure ratio has an average surfaceroughness of 6.0 nm or less. With the curable resin composition 11 usedin the present embodiment, this average surface roughness can be kept at6.0 nm or less, preferably at 5.0 or less, and more preferably in therange of 1 to 3 nm. Therefore, in practice, the distortion generated atthe interface of the cured resin can be ignored.

Preferred examples of the glass plate which may be used include theglass plate which sandwiches the liquid crystals of a liquid crystalcell, or the glass plate used as the protective plate for a liquidcrystal cell. Furthermore, preferred examples of an acrylic plate whichmay be used include the acrylic plate used as the protective plate for aliquid crystal cell. These glass plates or acrylic plates usually havean average surface roughness of 1.0 nm or less.

In the present invention, the viscosity of the curable resin composition11 is not especially limited. However, from the perspective of wetspreading rate and tendency not to protrude, the curable resincomposition 11 preferably has a viscosity (25° C., cone-plate typerotary viscometer, cone-plate taper angle C35/2°, 10 rpm) of 1,000 mPa·sto 5,000 mPa·s, and more preferably 2,000 mPa·s to 3,000 mPa·s.

Specific examples which may be preferably used include resincompositions containing at least one kind of polymer, such as apolyurethane acrylate, a polyisoprene acrylate or an ester thereof, ahydrogenated terpene resin, and a butadiene polymer; at least one kindof acrylate monomer, such as isobornyl acrylate, dicyclopentenyloxyethylmethacrylate and 2-hydroxybutyl methacrylate; and at least one kind ofphotopolymerization initiator, such as1-hydroxy-cyclohexyl-phenyl-ketone. Other additives, such as asensitizing agent, a plasticizer, transparent particles and the like,may also be added within the scope of the object of the presentinvention.

Here, as the photopolymerization initiator,1-hydroxy-cyclohexyl-phenyl-ketone (trade name: Iragacure 184,manufactured by Ciba Specialty Chemicals Inc.) may be preferably used.

The protective part 3 can have a UV-region cutting function to protectthe display part against ultraviolet rays. In such a case, as thephotopolymerization initiator, it is preferred to use aphotopolymerization initiator that can cure even in the visible region(for example, trade name: SpeedCure TPO, manufactured by NihonSiberHegner KK).

In the embodiment illustrated in FIG. 1, a pattern of the curable resincomposition 11 is coated on a protective part, and then, as illustratedin FIG. 1(b), the top and bottom of the protective part 3 are invertedso that the face provided with the curable resin composition 11 patternfaces perpendicularly down, and the protective part 3 is arranged facingup towards the base 2. Consequently, the surface of the coated curableresin composition 11 is less susceptible to being influenced by thesurface shape of the coating face 3 a of the protective part 3.Furthermore, the surface of the pattern of the resin composition 11 issmoother due to the combined forces of gravity and resin surfacetension. Therefore, the thickness of the resin filled between the base 2and the protective part 3 can be made more uniform, and air bubbles canbe reliably prevented from becoming mixed in the curable resincomposition 11.

Next, the protective part 3 is lowered in a horizontal state by apositioning and hoisting mechanism and positioning means(not-illustrated) to fix the protective part 3 at a given positionwithout the use of a spacer for determining an interval between the base2 and the protective part 3. The curable resin composition 11 coated onthe protective part 3 is brought into contact with the surface of thebase 2 to fill the curable resin composition 11 in the gap between thebase 2 and the protective part 3.

As illustrated in FIG. 1(c), UV-rays 33 are then irradiated via thelight-transmitting member 4 on a resin composition filled portion 13corresponding to the image display region.

The irradiation direction of the UV-rays 33 is not especially limited.However, from the standpoint of achieving more uniform curing of thecurable resin composition 11 on the image display region, the directionorthogonal to the surface of the light-transmitting member 4 ispreferred.

As illustrated in FIG. 1(c) and in FIG. 2, UV-rays 32 may also besimultaneously directly irradiated from the outward side direction ofthe bonding face 5 a of the shielding part 5 on a resin compositionfilled portion 12 between the shielding part 5 and the base 2, using aUV irradiation apparatus 31 having a fine irradiation part 30 formedfrom an optical fiber, for example.

The irradiation direction of the UV-rays 32 is not especially limited,and may be from 0° or more to less than 90° with respect to thehorizontal direction. However, from the standpoint of achieving moreuniform curing of the curable resin composition 11 on the forming regionof the shielding part 5, it is preferred to carry out the irradiation ofthe UV-rays 32 roughly parallel to the bonding face 6 a of the frame 6of the base 2 and the bonding face 5 a of the shielding part 5 of theprotective part 3.

By irradiating with such UV-rays 32 and 33, as illustrated in FIG. 1(d),the resin composition filled portions 12 and 13 are cured to form thecured resin layer 14 and obtain the intended image display apparatus 1.

The present invention is not limited to the above-described embodiment,and various changes may be carried out.

For example, the irradiation of the UV-rays 33 on the curable resincomposition 11 corresponding to the image display region and theirradiation of the UV-rays 32 on the curable resin composition 11corresponding to the shielding part may be carried out simultaneously,or in separate steps.

Furthermore, the present invention may be applied not only in theabove-described liquid crystal display apparatus, but also in variouspanel displays, such as an organic EL, a plasma display apparatus andthe like.

EXAMPLES

The present invention will now be described in more detail using thefollowing examples and comparative examples. However, the presentinvention is not limited to these examples and comparative examples.

Coating Solution Preparation

Example Resin 1

The resin composition of Example 1 was prepared by kneading in a kneader50 parts by weight of polyurethane acrylate (trade name: UV-3000B,manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 30 partsby weight of isobornyl acrylate (trade name: IBXA, manufactured by OsakaOrganic Chemical Industry Ltd.), 3 parts by weight of aphotopolymerization initiator (trade name: Irgacure 184, manufactured byCiba Specialty Chemicals Inc.), and 1 part by weight of aphotopolymerization initiator (trade name: SpeedCure TPO, manufacturedby Nihon SiberHegner KK).

Example Resin 2

The resin composition of Example 2 was prepared by kneading in a kneader70 parts by weight of an ester formed from a maleic anhydride adduct ofa polyisoprene polymer and 2-hydroxyethyl methacrylate, 30 parts byweight of dicyclopentenyloxyethyl methacrylate, 10 parts by weight of2-hydroxybutyl methacrylate, 30 parts by weight of a hydrogenatedterpene resin, 140 parts by weight of a butadiene polymer, 4 parts byweight of a photopolymerization initiator, and 0.5 parts by weight of avisible region photopolymerization initiator.

Example Resin 3

The resin composition of Example 3 was prepared by kneading in a kneader100 parts by weight of an ester formed from a maleic anhydride adduct ofa polyisoprene polymer and 2-hydroxyethyl methacrylate, 30 parts byweight of dicyclopentenyloxyethyl methacrylate, 10 parts by weight of2-hydroxybutyl methacrylate, 30 parts by weight of a hydrogenatedterpene resin, 210 parts by weight of a butadiene polymer, 7 parts byweight of a photopolymerization initiator, and 1.5 parts by weight of avisible region photopolymerization initiator.

Example Resin 4

The resin composition of Example 4 was prepared by kneading in a kneader70 parts by weight of an ester compound formed from a maleic anhydrideadduct of a polyisoprene polymer and 2-hydroxyethyl methacrylate (tradename: UC-203, manufactured by Kuraray Co., Ltd.), 30 parts by weight ofdicyclopentenyl oxyethyl methacrylate (trade name: FA512M, manufacturedby Hitachi Chemical Co., Ltd.), 10 parts by weight of 2-hydroxybutylmethacrylate (trade name: Light Ester HOB, manufactured by KyoeishaChemical Co., Ltd.), 30 parts by weight of a hydrogenated terpene resin(trade name: Clearon P-85, manufactured by Yasuhara Chemical Co., Ltd.),35 parts by weight of a butadiene polymer (trade name: Polyoil 110,manufactured by Zeon Corporation), 5 parts by weight of aphotopolymerization initiator (trade name Irgacure 184D, manufactured byCiba Specialty Chemicals Inc.), and 2 parts by weight of aphotopolymerization initiator (trade name SpeedCure TPO, manufactured byNihon SiberHegner KK).

Comparative Example Resin 1

The resin composition of Comparative Example 1 was prepared by kneadingin a kneader 50 parts by weight of polybutadiene acrylate (trade name:TE-2000, manufactured by Nippon Soda Co., Ltd.), 20 parts by weight ofhydroxyethyl methacrylate (trade name: Light Ester HO, manufactured byKyoeisha Chemical Co., Ltd.), 3 parts by weight of a photopolymerizationinitiator (trade name: Irgacure 184, manufactured by Ciba SpecialtyChemicals Inc.), and 1 part by weight of a photopolymerization initiator(trade name: SpeedCure TPO, manufactured by Nihon SiberHegner KK).

Comparative Example Resin 2

The resin composition of Comparative Example 3 was prepared by kneadingin a kneader 50 parts by weight of polyurethane acrylate (trade name:UV-3000B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.),30 parts by weight of tricyclodecane dimethanol acrylate (trade name: NKEster LC2, manufactured by Shin-nakamura Chemical Co., Ltd.), 3 parts byweight of a photopolymerization initiator (trade name: Irgacure 184,manufactured by Ciba Specialty Chemicals Inc.), and 1 part by weight ofa photopolymerization initiator (trade name: SpeedCure TPO, manufacturedby Nihon SiberHegner KK).

Comparative Example Resin 3

The resin composition of Comparative Example 3 was prepared by kneadingin a kneader 50 parts by weight of polybutadiene acrylate (trade name:TE-2000, manufactured by Nippon Soda Co., Ltd.), 20 parts by weight ofisobornyl acrylate (trade name: IBXA, manufactured by Osaka OrganicChemical Industry Ltd.), 3 parts by weight of a photopolymerizationinitiator (trade name: Irgacure 184, manufactured by Ciba SpecialtyChemicals Inc.), and 1 part by weight of a photopolymerization initiator(trade name: SpeedCure TPO, manufactured by Nihon SiberHegner KK).

Evaluation 1

The light transmittance, storage modulus, curing shrinkage ratio, andsurface roughness of Example Resins 1 to 4 and Comparative ExampleResins 1 to 3 were measured as described below. These results are shownin Table 1.

[Light Transmittance]

Each of the resin compositions was dropped onto a 100 μm-thick whiteglass plate to a given thickness. The plates were conveyed on aUV-conveyor in a UV irradiation apparatus to obtain cured resin samples.

The transmittance (%) of each sample (cured resin thickness of 100 μm)in the visible region was measured by a UV-Visible spectrophotometer(V-560, manufactured by JASCO Corporation).

[Storage Modulus]

Samples were produced in the same manner as the light transmittancesamples. The storage modulus (Pa) of each sample was measured using aviscoelastometer (DMS6100, manufactured by Seiko Instruments Inc.)(measurement frequency of 1 Hz, 25° C.)

[Curing Shrinkage Ratio]

The curing shrinkage ratio (%) was calculated by the following equationbased on the difference in the specific gravities between the uncuredresin solution and the cured solid product, as measured by an electronicdensimeter (SD-120L, manufactured by Mirage).Curing shrinkage ratio (%)=(Cured product specific gravity−Resinsolution specific gravity)/Cured product specific gravity×100  [Equation1][Surface Roughness Measurement]

2 mg of each resin composition was dropped onto a glass plate for aliquid crystal cell. The distortion (Ra: average surface roughness) in agiven region (2.93 mm×2.20 mm) of a glass plate surface formed by theinternal stress generated during the curing reaction from the UVirradiation was measured using a three-dimensional non-contact surfaceroughness meter manufactured by Zygo Corporation.

TABLE 1 Properties and Evaluation Results of Example Resins andComparative Example Resins Ra: Average Storage Curing SurfaceTransmittance Modulus Shrinkage Roughness (%) (Pa) Ratio (%) (nm)Example 90 or more 1 × 10⁶ 4.5 5.5 Resin 1 Example 90 or more 1 × 10⁴1.8 2.7 Resin 2 Example 90 or more 4 × 10³ 1.0 1.5 Resin 3 Example 90 ormore 4 × 10⁵ 3.8 5.0 Resin 4 Comparative 90 or more 2 × 10⁷ 5.6 12.4Example Resin 1 Comparative 90 or more 3 × 10⁸ 4.3 36.5 Example Resin 2Comparative 90 or more 5 × 10⁸ 5.6 64.2 Example Resin 3

As can be seen from Table 1, regarding transmittance, good resultswithout any problems were obtained for both the example resins and thecomparative example resins.

However, Example Resins 1 to 4 had a storage modulus of 4×10³ to 1×10⁶Pa and a curing shrinkage ratio of 1.0 to 4.5%. Consequently, theaverage surface roughness Ra was from 1.5 to 5.5 nm, and there washardly any distortion, meaning that good results were obtained.

In comparison, average surface roughness Ra was significantly large inComparative Example Resin 1 (Ra=12.4 nm), Comparative Example Resin 2(Ra=36.5 nm), and Comparative Example Resin 3 (Ra=64.2 nm), from whichit can be understood that the distortion at the interface between theresin and the glass plate was caused by the internal stress generatedduring curing of the resin.

Evaluation 2

Using the resin composition of Example Resins 1 to 4, the resincomposition wet spreading time and difference in thickness wereevaluated in the following manner for the example pattern illustrated inFIG. 1 and the comparative example pattern illustrated in FIG. 8. Theseresults are shown in Table 2.

Example Pattern

Using the resin composition of Example Resin 1, the above-describedresin composition pattern 21 illustrated in FIG. 4 and circular resincomposition patterns 24 a to 24 d were formed on a coating face 3 a ofthe protective part 3 side of the image display apparatus of FIG. 1. Theprotective part 3 was then inverted and arranged parallel with andfacing in close proximity to the liquid crystal display panel 8 of thebase 2 side to make the resin composition wetly spread between the base2 and the protective part 3.

The resin compositions of Example Resins 2 to 4 were made to wetlyspread between the base 2 and the protective part 3 in the same manneras the resin composition of Example Resin 1.

Comparative Example Pattern

The resin composition of Comparative Example Resin 1 was made to wetlyspread between the base 2 and the protective part 3 in the same manneras described above, except that the elliptical pattern 50 illustrated inFIG. 8 was formed on a middle portion of the coating face 3 a of theprotective part 3.

[Measurement of Unevenness in Resin Thickness]

The wet spreading time and unevenness in resin thickness were calculatedfor the resin compositions filled between the base 2 and the protectivepart 3.

The unevenness in resin thickness was determined by measuring the totalthickness of the image display apparatus (FIG. 1(d)) on which the base 2and the protective part 3 were bonded with a film thickness meter(μMate, manufactured by Sony Corporation) at a total of five points ofthe bonded region, the center and the four corners, and determining theratio (%) of deviation with respect to a standard thickness (100 μm) foreach of the measured values. The unevenness in resin thickness was thencalculated from the variation (σ²) among the deviation ratios.

TABLE 2 Wet Spreading Unevenness in Time (minute Resin Thicknesscomparison) (σ) Example Pattern 0.1 5% or less (Example Resins 1 to 4)Comparative Example 1 30% Pattern (Comparative Example Resin 1)

As can be seen from Table 2, regarding the wet spreading time of theresin compositions, when the example pattern was used, for all ofExample Resins 1 to 4, the filling of the resin composition could becarried out in 1/10 of the wet spreading time of that of the comparativeexample pattern.

Furthermore, regarding unevenness in resin thickness, the examplepattern obtained better results than the comparative example pattern(30%).

In this case, for Example Resin 1, the unevenness in resin thickness was5%, and for Example Resins 2 to 4, the unevenness in resin thickness wasless than 5%.

Based on these results, it can be understood that according to thepresent invention a resin composition can be filled between the base 2and the protective part 3 of the image display apparatus in a uniformthickness and in a short time.

INDUSTRIAL APPLICABILITY

The present invention is useful in the production of an image displayapparatus such as a liquid crystal display apparatus.

The invention claimed is:
 1. A method for producing an image displayapparatus comprising: (a) coating a curable resin composition having acuring shrinkage ratio of 5% or less onto a base having an image displaypart or onto a light-transmitting protective part arranged on the imagedisplay part, wherein the curable resin composition coated onto the baseor the protective part has a pattern with a prescribed shape formedfrom: (i) a center pattern positioned in the center portion of thecoating face of the base or the protective part, and the center patternis formed in a belt pattern extending linearly in a direction of a longside of the base or the protective part, (ii) a corner patternpositioned adjacent to a corner of the coating face and which iscontinuous with or separated from the center pattern, and the cornerpattern is formed in an arm portion pattern that branches out andextends in four directions from either end of the center pattern, withthe arm portion pattern being arranged on a reference line from eitherend of the center pattern to each corner of a coating face of the baseor the protective part, and (iii) a circular resin composition patternthat is separate from the center pattern and the corner pattern and thatis formed between an end of the corner pattern and each of the corner ofthe coating face of the base or the protective part, wherein a thicknessof the curable resin composition at the center portion of a coating faceof the base or the protective part is thicker than a thickness of thecurable resin composition at a corner portion of the coating face ofbase or the protective part, and the thickness of the curable resincomposition tapers downwardly from the center portion of the coatingface of the base or the protective part to a periphery of the cornerportion of the coating face of base or the protective part; (b) thenarranging the base and the protective part to face each other in closeproximity so that the curable resin composition is made to spreadbetween the base and the protective part; and (c) then forming a curedresin layer between the base and the protective part by curing thecurable resin composition, wherein the cured resin layer has a storagemodulus of from 1×10³ Pa to 1×10⁶ Pa at 25° C., and a lighttransmittance of the cured resin layer in a visible region is 90% ormore.
 2. The production method according to claim 1, wherein thecircular resin composition pattern is arranged on the reference line. 3.The production method according to claim 1, wherein the curable resincomposition is coated on both the base and the protective part.
 4. Theproduction method according to claim 1, wherein the curable resincomposition has a curing shrinkage ratio of 4.0% or less.
 5. Theproduction method according to claim 1, wherein the cured resin layerhas a thickness of 50 to 200 μm.
 6. The production method according toclaim 1, wherein the image display part is a liquid crystal displaypanel.
 7. The production method according to claim 1, wherein theprotective part is formed from an acrylic resin.
 8. The productionmethod according to claim 1, wherein the protective part is formed froman optical glass.